@article{VinnikSilveiraKiselevetal.2012,
  author    = {Vinnik, Lev and Silveira, Graca and Kiselev, Sergei and Farra, Veronique and Weber, Michael H. and Stutzmann, Eleonore},
  title     = {Cape verde hotspot from the upper crust to the top of the lower mantle},
  series = {Earth \& planetary science letters},
  volume    = {319},
  journal   = {Earth \& planetary science letters},
  number    = {4},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0012-821X},
  doi       = {10.1016/j.epsl.2011.12.017},
  pages     = {259 -- 268},
  year      = {2012},
  abstract  = {We investigate the crust, upper mantle and mantle transition zone of the Cape Verde hotspot by using seismic P and S receiver functions from several tens of local seismograph stations. We find a strong discontinuity at a depth of similar to 10 km underlain by a similar to 15-km thick layer with a high (similar to 1.9) Vp/Vs velocity ratio. We interpret this discontinuity and the underlying layer as the fossil Moho, inherited from the pre-hotspot era, and the plume-related magmatic underplate. Our uppermost-mantle models are very different from those previously obtained for this region: our S velocity is much lower and there are no indications of low densities. Contrary to previously published arguments for the standard transition zone thickness our data indicate that this thickness under the Cape Verde islands is up to similar to 30 km less than in the ambient mantle. This reduction is a combined effect of a depression of the 410-km discontinuity and an uplift of the 660-km discontinuity. The uplift is in contrast to laboratory data and some seismic data on a negligible dependence of depth of the 660-km discontinuity on temperature in hotspots. A large negative pressure-temperature slope which is suggested by our data implies that the 660-km discontinuity may resist passage of the plume. Our data reveal beneath the islands a reduction of S velocity of a few percent between 470-km and 510-km depths. The low velocity layer in the upper transition zone under the Cape Verde archipelago is very similar to that previously found under the Azores and a few other hotspots. In the literature there are reports on a regional 520-km discontinuity, the impedance of which is too large to be explained by the known phase transitions. Our observations suggest that the 520-km discontinuity may present the base of the low-velocity layer in the transition zone.},
  language  = {en}
}
@article{ValesDiasRioetal.2014,
  author    = {Vales, Dina and Dias, Nuno A. and Rio, Ines and Matias, Luis and Silveira, Graca and Madeira, Jose and Weber, Michael H. and Carrilho, Fernando and Haberland, Christian},
  title     = {Intraplate seismicity across the Cape Verde swell: A contribution from a temporary seismic network},
  series = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth},
  volume    = {636},
  journal   = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0040-1951},
  doi       = {10.1016/j.tecto.2014.09.014},
  pages     = {325 -- 337},
  year      = {2014},
  abstract  = {We present an analysis and characterization of the regional seismicity recorded by a temporary broadband seismic network deployed in the Cape Verde archipelago between November 2007 and September 2008. The detection of earthquakes was based on spectrograms, allowing the discrimination from low-frequency volcanic signals, resulting in 358 events of which 265 were located, the magnitudes usually being smaller than 3. For the location, a new 1-D P-velocity model was derived for the region showing a crust consistent with an oceanic crustal structure. The seismicity is located mostly offshore the westernmost and geologically youngest areas of the archipelago, near the islands of Santo Antao and Sao Vicente in the NW and Brava and Fogo in the SW. The SW cluster has a lower occurrence rate and corresponds to seismicity concentrated mainly along an alignment between Brava and the Cadamosto seamount presenting normal faulting mechanisms. The existence of the NW cluster, located offshore SW of Santo Antao, was so far unknown and concentrates around a recently recognized submarine cone field; this cluster presents focal depths extending from the crust to the upper mantle and suggests volcanic unrest No evident temporal behaviour could be perceived, although the events tend to occur in bursts of activity lasting a few days. In this recording period, no significant activity was detected at Fogo volcano, the most active volcanic edifice in Cape Verde. The seismicity characteristics point mainly to a volcanic origin. The correlation of the recorded seismicity with active volcanic structures agrees with the tendency for a westward migration of volcanic activity in the archipelago as indicated by the geologic record. (C) 2014 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{MatosSilveiraMatiasetal.2015,
  author    = {Matos, Catarina and Silveira, Graca and Matias, Luis and Caldeira, Rita and Ribeiro, M. Luisa and Dias, Nuno A. and Kr{\"u}ger, Frank and Bento dos Santos, Telmo},
  title     = {Upper crustal structure of Madeira Island revealed from ambient noise tomography},
  series = {Journal of volcanology and geothermal research},
  volume    = {298},
  journal   = {Journal of volcanology and geothermal research},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0377-0273},
  doi       = {10.1016/j.jvolgeores.2015.03.017},
  pages     = {136 -- 145},
  year      = {2015},
  abstract  = {We present the first image of the Madeira upper crustal structure, using ambient seismic noise tomography. 16 months of ambient noise, recorded in a dense network of 26 seismometers deployed across Madeira, allowed reconstructing Rayleigh wave Green's functions between receivers. Dispersion analysis was performed in the short period band from 1.0 to 4.0 s. Group velocity measurements were regionalized to obtain 20 tomographic images, with a lateral resolution of 2.0 km in central Madeira. Afterwards, the dispersion curves, extracted from each cell of the 2D group velocity maps, were inverted as a function of depth to obtain a 3D shear wave velocity model of the upper crust, from the surface to a depth of 2.0 km. The obtained 3D velocity model reveals features throughout the island that correlates well with surface geology and island evolution. (C) 2015 Elsevier B.V. All rights reserved.},
  language  = {en}
}